Specimen b of tables



3,172,761 BERYLLIUM-NIOBIUM COMPOSITION Wallace W. Beaver, ShakerHeights, Robert M. Paine,

Lakewood, and Albert James Stonehouse, Lyndhurst, Ohio, assignors to TheBrush Beryllium Company, Cleveland, Ohio, a corporation of Ohio NoDrawing. Original application May 9, 1960, Ser. No. 27,523. .Divided andthis application Jan. 21, 1963, Ser. No. 252,621

1 Claim. (Cl. 75-150) This is a division of application Serial No.27,523, filed May 9, 1960.

This invention relates to binary intermetallic compound-compositions, tobodies composed thereof, and to methods of making thecompound-compositions and bodies thereof.

The invention relates more specifically to binary intermetalliccompound-composition bodies which are of fine grain, havingsubstantially the theoretical density of the intermetalliccompound-composition of which they are composed, and which, attemperatures ranging from as high as 2000 F. to 2900 F., have extremelyhigh resistance to oxidation and extremely great strength.

Important features reside in the steps of the preferred method by whichthe starting binary intermetallic compound-composition in the powderedform are produced, and of the preferred method by which the powders areformed into the bodies having thephysical properties above described.

Another feature is to form the bodies of the basic binary intermetalliccompound-compositions in which the metals are of such non-stoichiometricproportions as to increase the mechanical strength at the elevatedtemperatures over that which the bodies would have if the proportions ofthe two metals were stoichiometric.

Various objects and advantages of the invention will become apparentfrom the following description wherein specific examples of thecompound-compositions and methods of producing the same and the bodiesare shown by way of illustration.

The binary intermetallic compound-compositions of the present invention,in some cases, partake of the characteristics of compounds, and in othercases, of the characteristics of alloys. In some cases their exactnature is not determinable with certainty. Accordingly, they are allreferred to hereinafteras compound-compositions.

The binary intermetallic compound-compositions of the present inventionconsists essentially of two metals, one selected from a first groupconsisting of beryllium and aluminum, and another metal M selected froma second group consisting ofniobium, zirconium, tantalum and molybdenum.

- By the term consisting essentially of, it is meant to exclude anyother. metal or materials subversive of the characteristics of thesubstantially pure binary intermetallic compound-compositions.

The beryllium from the first group can be combined with any one of themetals from the second group. The aluminum of the first group can becombined with any one of the metals of the second group, but theoutstanding advantages of the binary intermetallic compound-compositionscontaining aluminum are obtainable only when the aluminum is combinedwith eitherniobium or tantalum.

The ratio, by weight, of the metal of the first group to that of thesecond group can be any ratio desired in a broad range wherein metalfrom neither group is less than about 20% of the combined weight of thetwo metals, the balance consisting essentially of a metal from thesecond group, and the beryllium from the first group does not exceedsubstantially its stoichiometric proportion corresponding to MBe and MBeand the aluminum from the first group does not exceed substantially itsstoichiometric atent O proportion corresponding to MAl wherein M is ametal selected from the group consisting of niobium, zirconium,

tantalum and molybdenum. Some of the metals, when I used within morelimited ratios within these broader ranges, have additional andparticularly outstanding qualities.

The metals of both groups preferably are substantially pure. For themost outstanding results, the binary intermetallic compound-compositionshereof preferably have total impurities not exceeding about 1%, byweight, of their total weight.

The methods of producing the basic intermetallic compound-compositionsare as follows:

In one method, the selected metals, one from each group, in the form ofpowder of particle size of about 50 mesh or finer, are intimatelyintermixed and reacted to completion. They may be reacted by melting inwhich case the resultant product is extremely hard and diificult to,pulverize to form a powder for forming the final bodies.

The preferred methods are to-efiect the reaction of the metals in asolid state, at sintering temperatures, and below the temperature atwhich appreciable melting or fusion would occur, to produce a friablecompact of the binary intermetallic compound-compositions, which compactis readily pulverizable to a particle size of about 200 pressure in thefurnace is thereby lowered, preferably to less than one micron ofmercury.

Heat is then applied, starting at room temperature, preferably by meansof an adjustable electric resistance heating element so that accuratecontrol of the heating is obtainable. The heat is applied so asgradually to bring the compact up to a temperature of about 450 C.During this initial heating period,moisture and occluded and evolvedgases are driven out of the compact and drawn off by the vacuum pumpfrom the crucible and compact. As they are evolved and freed, thefurnacepressure tends to rise, but is maintained generally at less than tenmicrons, and preferably at less than one micron of mercury,

by the continuance of the evacuation.

As one example of a compachabout cubic centimeters, by volume, of themixture of the two metallic powders are subjected preferably to about 30tons per square inch of mechanical pressure, at room tempera-' ture.This produces a cold compact of about 65% of theoretical density.

As an alternate method, the compacting step may be omitted and theselected mixture of powdered metals may be reacted in loose form,the'other steps, conditions, and proportions, remaining unchanged.

Compacting has the advantage of convenience in handling the metals andcharging the crucible. In addition,

to 1400 C. This higher temperature, together with the vacuum, iscontinued for about one hour.

heating and with the vacuum continuing,

. 3 Next the heat is turned off, and with the vacuum continued, thecompact is allowed to cool to less than 100 C., after which it isremoved from the furnace.

The exact period of time of heating may be varied for processing eachmixture can be established without loss of valuable metal.

In the foregoing sintering methods, an inert atmosphere may besubstituted for the vacuum throughout the practice of the entire method.However, to obtain compositions of the highest purity, the mixtureshould be substantially evacuated prior to reaction in the inertatmosphere.

The following Examples 19 are illustrative of the preparation of thebasic powder of intermetallic compound-compositions, and are, specificto our method whether the compacting step is omitted or not, and whetheror not the recited substitution of inert atmosphere for vacuum is made,the other steps, conditions, and proportions remaining unchanged. Forberyllium and niobium compositions the examples show arange forberyllium of from about 45.2% to 53.6%, range being from about 46.4% to51.6%.,

EXAMPLE l.BERYLLIUM-NIOBIUM Finely powdered beryllium, in an amount of3.50 kilograms, was intimately mixed with 3.017 kilograms of the finelypowdered niobium, both materials being of a particlesize of 50 mesh orfiner. The intimate intermixture was then compacted at room temperatureat a pressure of about 30 tons per square inch. The cold pressed compactwas placed in the graphite crucible in a furnacechamber' which was thenevacuated while at room temperature to a pressureof less than one micronof mercury. As soon as this degree ofevacuation was reached, heat wasapplied and the compact heated gradually to 450 C., while continuing theevacuation. The

evacuation were continued until the compact was substantially free frommoisture and occluded gases and vapors. Thereupon the rate of heatingwas increased by about 100 C. per hour until a maximum temperature ofabout 1270 C. was reached, the vacuum meanwhile being continued. Thismaximum temperature and concurrent evacuation were continued for aboutone hour. Thereupon the heating was then discontinued, but the furnacewas cooled to room temperature. 'The product of this reaction was afriable and porous compart. It was removed from the furnace and waseasily pulverized to powder having a particle size of 200 mesh or finer.The beryllium content determined by chemical analysis was 53.6% byweight, of

the intermetallic compound-composition, the balance consistingessentially of niobium.

EXAMPLE 2.BERYLLIUM-NIOBIUM EXAMPLE 3.-BERYLLlUM-Z IRCONIUM Theprocedure of Example 1 was followed using 3.461 ltiiograms of berylliumand 2.644 kilograms of zirconium. By chemical analysis, the berylliumcontent was 56% by weight of the intermetallic compound-composition, thebalance consisting essentially of zirconium.

EXAMPLE 4.BERYLLIUM-ZIRCONIUM The procedure of Example 1 was followedusing 524.3 grams of beryllium and 622.7 grams zirconium. The berylliumcontent determined by chemical analysis was 45.7% by weight of theintermetallic compound-composition, the balance consisting essentiallyof zirconium.

EXAMPLE 5.BERYLLlUM-TANTALUM The procedure of Example 1 was followedusing 1.908 kilograms of beryllium and 3.192 kilograms of tantalum. Theberyllium content, determined by chemical analysis, was 37.2% by weightof the intermctallic compoundcomposition, the balance consistingessentially of tantalum.

EXAMPLE 6.---BERYLLIUM-TANTALUM The procedure of Example 1 was followedusing 540.2 grams of beryllium and 1247 ,grams of tantalum. Theberyllium content, determined by chemical analysis, was 29.8% by weightof the intermetallic compound-composition, the balance consistingessentially of tantalum.

EXAMPLE 7.BERYLLIUM-MOLYBDENUM EXAMPLE 8.ALUMINUM-NIQOBIUM The procedureof Example 1 was followed using 282 grams of aluminum and 324 grams ofniobium. The

aluminum content, determined by chemical analysis, was

46.5% by weight of the intermetallic compound-composition, the balanceconsisting essentially of niobium.

EXAMPLE 9.ALUMINUM-TANTALUM The procedure of Example 1 was followedusing 258 grams of aluminum and 577 grams of tantalum; By chemicalanalysis, the aluminum content was 30.9% by weight of the intermetalliccompound-composition, the balance consisting essentially of tantalum.

Having prepared the basic pulverized intermetallic compound-compositionpowder, the next step is to form any selected one of them into bodieshaving a fine grain, a density of substantiallyv the calculatedtheoretical density, and high oxidation resistance and high strength attemperatures of from 2000-2900 F. To this end, the pulverizedintermetallie compound-composition powder, preferably of a particle sizeof 200 mesh or finer, is charged into a graphite die havingsubstantially the internal configuration desired for the exterior of thebody to be produced.

The charge and die are subjected, in a furnace at room temperature, toconcurrent evacuation and application of mechanical pressure of about1000 pounds per square inch. The evacuation and mechanical pressure arecontinued until the furnace chamber, with the charged die therein, isevacuated to a furnace pressure not to exceed 1000 microns of mercury,and preferably as low as 40 microns of mercury. Beginning when thefurnace pressure has reached relative stability, indicating thatsubstantially all the gases and vapors have been removed, and with themechanical pressure and the vacuum continued, heat is applied.

The temperature is increased and the mechanical pressure is concurrentlyincreased to a maximum of about 000 pounds per square inch as thetemperature increases until substantially complete compaction andmaximum density are obtained, usually at about 1400 C. to about 1650" C.When this latter temperature and pressure are reached, the applicationof mechanical pressure is discontinued, but the vacuum and elevatedtemperature are continued thereafter until the stresses developed in thebody by the preceding steps are relieved. This latter step, which, ingeneral, is an annealing step, generally requires about one-half hourfor small compacts.

After the body is annealed, heating is discontinued and the furnace,die, and body are cooled gradually, under vacuum, to room temperature,after which the body is ready for removal and use.

As mentioned, the beryllium and aluminum may be used in amounts as lowas 20%, by weight of the body, up to but not to exceed stoichiornetricproportions of, in the case of beryllium, MBe and MBC13, and in the caseof aluminum, MAl wherein M is a metal selected from the group consistingof niobium, zirconium, tantalum and molybdenum, in any instance. Ifeither beryllium or aluminum is used in amounts less than stoichiometricproportions, it cannot with certainty be said that the resultantmaterial is a true compound. Instead, it partakes somewhat of the natureboth of a true compound and a mixture of compounds.

A large number of intermetallic compound-compositions, some of which areof various phases, can be produced by selecting predetermined ratios ofthe selected starting powders.

The strength and oxidation resistance properties of the variousintermetallic compound-compositions, at the elevated temperatures, varyfor different proportions of the selected metals.

Generally, when a greater proportion of beryllium or aluminum than astoichiometric proportion of the more beryllium-rich, MBe and MBe13 andaluminum-rich, MAl respectively, compound-compositions of our inventionis used as the upper limit of the range, in producing the binaryintermetallic compound-composition powders, the compound-compositionloses its high strength and oxidation resistance properties at theelevated temperatures. The loss of these desirable properties isbelieved to be attributable to the presence of free or unreactedberyllium or aluminum, either of which melts at a lower temperature than2350 F. In the case of very small amounts of the free metal, porosityand cracking result, andin the case of larger amounts, the meltingprevents the formaiton of a solid and dense body, at the hot-press ringtemperatures employed in our method. These upper substantiallystoichiometric limits of beryllium or aluminum of the aboveberyllium-rich and aluminum-rich compound-compositions of our inventionare the upper critical limits, and preferably should not be exceeded atall, and certainly by not more than a small fraction of a percent.Surprisingly, the inclusion of these metals in less than stoichiometricproportions produces, in some instances, the greatest mechanicalstrength at elevated temperatures. 7

On the other hand, the lower limits of the specified ranges of berylliumand aluminum are not as critical, since the intermetalliccompound-compositions containing ten to fifteen percent, by weight, ofberyllum or aluminum are nevertheless of high melting point. The recitedranges, however, cover those intermetalliccompoundcompositions whichexhibit the most favorable grain size, density, oxidation resistance,and high strength, at elevated temperatures from 20002900 F.

It should be realized that the metal powders employed in the preparationof the intermetallic compound-compositions, as in the case of mostmetals, contained minor impurities. However, the beryllium powder usedwas 99.0% or more pure, and contained mainly beryllium oxide and veryminor amounts of heavy metals and aluminum as'impurities. Such highpurity is preferred, but impurities up to about 3% may be tolerated insome instances. The niobium, tantalum, molybdenum, and zirconium powdersused were at least about 99.5% pure.

Analysis of the examples thereinafter given discloses that the binaryintermetallic compound-compositions of upon removal from the furnace,weighed 167.6 grams the present invention were not or pure, buttypically contained one or more of the following impurities in thepercentages indicated.

Percent by weight of binary inter- Impurilyl metalliccompoundcompositlou O 0.8-1.0 Fe 0.05-0.07

Al 0.01-0.02 Si 0.001-0.0l

C 0.07-0.09 Cr, Ni, Mg, Mn (total) 0.0l00.0l5

gain-in-weight data were obtained by exposing weighedspecimen bodies ofeach intermetallic compound-composition to a 100 cubic centimeter perminute flow of either dry or moist air for 100 hours at the respectivetemperatures indicated in Table II hereof. The specimens were thenre-weighed to determine the increase in weight which isrepresentative ofthe oxidation resistance for each composition.

The penetration data, also indicative of the oxidation resistance ofthese compositions, were calculated from the gain-in-weight data, on theassumption that the gains occurred by oxidation and that allcompositions oxidized stoichiometrically. The compound-compositionswhich showed penetration of less than 2 mils in 100 hours exposure areconsidered to have good oxidation resistance in the indicatedtemperature ranges.

-Examples of the method of forming the bodies, and

physical properties of the formed bodies follow. Some of the relevantdata are tabulated and referenced in Tables I and II by reference totheir example numbers. Examples of the formation of bodies by theforegoing method are as follows:

EXAMPLE 10 (SPECIMEN A OF TABLES) evacuated while at room temperature.Beginning when the gases and vapors were substantially evacuated, heatwas applied while maintaining mechanical pressure and vacuum. Thetemperature was increased gradually and the mechanical pressure wasconcurrently increased, the vacuum concurrently being continued, until atemperature of about 1550 C. anda pressure of about 2000 psi. werereached.- The mechanical pressure was then discontinued, the vacuum andtemperature being continned for about another 20 minutes. Thcreupon, the

heating was discontinued, and the furnace was allowed to cool, undervacuum, to room temperature. The body,

and had a density of 2.88 g./cc., which is-98% of the calculatedtheoretical density. The grain size was 11 microns, and the berylliumcontent, determined by chemical analysis, was 53.6%, by weight, of thebody, the balance consisting essentially of niobium.

The furnace pressure reached during the initial substantial evacuationof the gases and vapors varies with different charges, the controllingfeature being the sub-' In this specific stantial removal of gases andvapors. example, the furnace pressure was microns of mercury. Thesubsequent evacuation 'was sufficient to rapidly' remove the gases andvapors evolved during the heating and pressing, and in this example, thepressure ranged from 500 to 1000 microns of mercury.

EXAMPLE 11 (SPECIMEN B OF TABLES) An intermetallic compound-compositionpowder, in an amount of 254 grams, consisting of 51.6%, by weight, ofberyllium, with the balance consisting essentially of niobium, andhaving a particle size of 200 mesh or finer, was placed in a graphitedie in a furnace. Following the procedure of Example 10, the temperatureand mechanical pressure were increased to a maximum of about 1520 C. and2000 p.s.i. concurrently during the maintenance of the vacuum. Themechanical pressure was then discontinued, and the concurrent maximumtemperature and vacuum maintained for about a half hour, after whichtime the heating was discontinued, and the furnace cooled under vacuumto room temperature. The body, upon removal from the furnace, weighed217.5 grams, and had a density of 2.99 g./cc., which is 99.7% of thecalculated theoretical density. Upon chemical analysis, its berylliumcontent was found to be 51.6%, by weight, of the body, with the balanceconsisting essentially of niobium, and its grain size was microns.

The furnace pressure during the initial evacuation was 500 microns ofmercury, and during the subsequent evacuation ranged from 300 to 500microns of mercury.

EXAMPLE 12 (SPECIMEN E OF TABLES) Following the procedure of Example 10,309 grams of powdered intermetallic compound-composition consisting of46.4% by weight of beryllium, and the balance consisting essentially ofniobium, and having a particle size of 200 mesh or finer, were placed inthe die. During the concurrent maintenance of temperature, mechanicalpressure, and vacuum, the gradual increase was to a maximum temperatureof about 1520 C. and to a mechanical pressure of about 2000 p.s.i. Thepressure was then discontinued and the concurrent maximum temperatureand evacuation were continued for about a half hour, after which theheating was discontinued and the furnace cooled under vacuum to roomtemperature, The body, upon removal from the furnace, weighed 297 gramsand had a density of 3.08 g./cc., which is 97.5% of the calculatedtheoretical density. The grain size was 15 microns and chemical analysisshowed the body to contain beryllium in an amount, by weight, of 46.4%of the body, with the balance consisting essentially of niobium.

The pressure during the initial substantial evacuation was 200 micronsof mercury, and during the subsequent evacuation ranged from 180 to 250microns of mercury.

EXAMPLE l3 (SPECIMEN F OF TABLES) Following the procedure of Example 10,264 grams of an intermetallic compound-composition consisting of 45.2%,by weight, of beryllium and the balance consisting essentially ofniobium, in powder form, and having a particle size of 200 mesh orfiner, were introduced into a die. The increase in temperature andpressure were to a maximum temperature of about 1550 C; and a maximummechanical pressure of about 2000 p.s.i., the pres body, with thebalance consisting essentially of niobium.

The pressure during the initial substantial evacuation was 40 microns ofmercury, and during the subsequent evacuation, ranged'from 100 to 250microns of mercury.

EXAMPLE 14 (SPECIMEN G OF TABLES) An intermetallic compound-composition,in powdered form and in the amount of 163.2 grams, consisting of 56% byweight of beryllium and the balance consisting essentially of zirconium,and having a particle size of 200 mesh or finer, was introduced into thedie within a furnace. Following the procedure of Example 10, the furnacewas evacuated concurrently with the application of about 1000 p.s.i. ofmechanical pressure. The vacuum was maintained and heat was applied,accompanied by a concurrent increase of mechanical pressure. During theconcurrent evacuation and application of mechanical pressure and heat, amaximum temperature of about l550 C. and a maximum pressure of about2000 p.s.i. were attained. At this time, the pressure was discontinued,and the evacuation and temperature were maintained concurrently forabout a half hour, after which time the furnace and die were cooledunder vacuum to room temperature. the furnace, weighed 154.9 grams, andhad a density of 2.77 g./cc., which is 99.3% of the calculatedtheoretical density. The grain size was 25 microns. The body was foundby chemical analysis to contain beryllium in an amount equal to 56% ofthe body, with the balance substantially only zirconium.

The pressure during the initial substantial evacuation was 180 micronsof mercury, and during the subsequent evacuation, was about 1000 micronsof mercury.

EXAMPLE l5 (SPECIMENI OF TABLES) In accordance with the procedure ofExample 10, 513 grams of an intermetallic compound-composition in powderform, consisting of 51.5% by weight of beryllium and the balanceconsisting essentially of zirconium, and having a particle size of 200mesh or finer, were introduced into the die in a furnace. During theconcurrent application of heat, mechanical pressure and evacuation, theincrease of temperature was up to a maximum temperature of about 1550 C.The increase in mechanical pressure was up to a maximum of about 2000p.s.i. The maximum pressure was then discontinued, and the maximumtemperature, with evacuation, maintained for about 40 minutes. Theheating was then discontinued, and the furnace allowed to cool to roomtemperature, under vacuum. The body, upon removal, weighed 488.6 grams,and had a density of 2.84 g./cc., corresponding to 98.6% of thecalculated theoretical density. The grain size was 24 microns. Chemicalanalysis disclosed 51.5% of beryl lium by weight, of the body, and thebalance consisting essentially of zirconium.

The pressure during theinitial substantial evacuation was 150 microns ofmercury, and during the subsequent evacuation ranged from 75 to 150microns of mercury.

EXAMPLE l6 (SPECIMEN M OF TABLES) Following the procedure of Example 10,240 grams of an intermetallic compound-composition powder, consisting of45.7% by weight of beryllium, the balance consisting essentially ofzirconium, and having a particle size of 200 mesh or finer, wereintroduced into the die. During the evacuation with a concurrentincrease in mechanical pressure and in temperature, a maximumtemperature of about l550 C. and a maximum mechanical prcsusre of about2000 p.s.i. were attained. The mechanical pres sure was thendiscontinued, and the concurrent evacuation and maximum temperaturemaintained for about a half hour, after which time the heating wasdiscontinued and the furnace vacuum cooled to room temperature. Thebody, upon removal, Weighed 225 grams, and had a density of 3.06 g./cc.,corresponding to ofthe calculated theoretical density. The grain sizewas 30 microns, and chemical analysis showed the body to containberyllium in an amount 45.7% by weight, of the body, the balanceconsisting essentially of zirconium.

The body, upon removal from- The pressure during the initial substantialevacuation was 40 microns of mercury, and during the subsequentevacuation ranged from 200 to 500 microns of mercury.

EXAMPLE 17 (SPECIMEN N OF TABLES) In accordance with the procedure ofExample 10, an intermetallic compound-composition in powder form, in anamount of 345 grams, and consisting of 37.2% by weight of beryllium andthe balance consisting essentially of tantalum, and having a particlesize of 200 mesh or finer, was introduced into the die, and the furnacewas then evacuated while applying about 1000 p.s.i. of mechanicalpressure. When the furnace was substantially evacuated, heat was appliedand increased, accompanied by a concurrent increase in the mechanicalpressure to about 1550 C. and about 2000 p.s.i. Thereupon, the pressurewas discontinued, and the maximum temperature and concurrent evacuationwas maintained for about a half hour, after which time the heating wasdiscontinued, and the furnace vacuum cooled to room temperature. Thebody, when removed, weighed 328 grams and had a density of 4.11 g./cc.,corresponding to 96.9% of the calculated theoretical density. The grainsize was 12 microns, and chemical analysis showed 37.2% by weight ofberyllium with the balance consisting essentially of tantalum.

The pressure during the initial substantial evacuation was 800 micronsof mercury, and during the subsequent evacuation was about 800 micronsof mercury.

EXAMPLE 18 (SPECIMEN Q OF TABLES) In accordance with the procedure ofExample 10, 900 grams of an intcrmetallic compound-compositionconsisting of 29.8% by weight of beryllium and the balance consistingessentially of tantalum, and having a particle size of 200 mesh or fineris disposed in the graphite die in a furnace. During the concurrentevacuation, and application of increasing heat and pressure, the maximumtemperature attained was about 1550 C. and maximum mechanical pressureof about 2000 p.s.i. When these maxiwas 200 microns of mercury, andduring the subsequent evacuation ranged from 175 to 250 microns ofmercury.

EXAMPLE 19 (SPECIMEN R OF TABLES) In accordance with the procedure ofExample 10, 250 grams of an intermetallic compound-compositionconsisting of 53% by weight of beryllium and the balance consistingessentially of molybdenum, and having a particle size of 200 mesh orfiner, were introduced in the die in a furnace. During the concurrentevacuation and the increase in application of mechanical pressure andheat, a

continued until thefurnace is cooled to room temperature.

The body weighed 236 grams, and had a density of 3.02 g./cc.,corresponding to 97.7% of the calculated theoretical density. The grainsize was 16 microns and chemical analysis showed 53% beryllium by weightof the body, the balance consisting essentially of molybdenum.

The pressure during the initial substantial evacuation was 45 microns ofmercury, and during the subsequent evacuation ranged from 200 to 500microns of mercury.

EXAMPLE 20 (SPECIMEN S OF TABLES) An intermetallic compound-composition,in an amount of 205.65 grams, and consisting of 46.5% by weight ofaluminum and the balance consisting essentially of niobium, and having aparticle size of 200 mesh or finer, was introduced in the graphite die.In accordance with the procedure of Example 10, the furnace was thenevacuated at room temperature during a concurrent application of about1000 p.s.i. mechanical pressure. When the furnace was substantiallyevacuated, heat was applied and the pressure was concurrently graduallyincreased, the evacuation being continued. The concurrent evacuation,application of heat, and increase in mechanical pressure continued untila maximum temperature of about 1465 C. and a maximum pressure of about2000 p.s.i. were reached. The pressure was then discontinued, and theconcurrent maximum temperature and evacuation maintained for about ahalf hour, after which the heating was discontinued, the vacuumcontinued and the furnace cooled to room temperature. The body was thenremoved from the furnace. It weighed 197.5 grams, and had a density of4.36 g./ce., which corresponds to 95.4% of the calculated theoreticaldensity. The grain size was 25 microns and chemical analysis showed46.5% aluminum by weight of the body, with the balance consistingessentially of niobium.

EXAMPLE 21 (SPECIMEN T OF TABLES) Following the procedure of Example 10,346 grams of an intermetallic compound-composition consisting of 30.9%by weight of aluminum and the balance consisting essentially oftantalum, and having a particle size of 200 mesh or finer, wereintroduced into a graphite die located in a furnace. During theconcurrent evacuation and increase of heat and mechanical pressure, amaximum temperature of about 1465 C. and a maximum pressure of about2000 p.s.i. were reached; As soon as the maximum temperature andpressure were reached, the mechanical pressure was'discontinued, and themaximum I temperature and evacuation maintained for about a half hour.With the evacuation continuing, the furnace was cooled to roomtemperature. moved, and weighed 288.8 grams, and had a density of 6.60g./ce., which corresponds to 95.4% of' the calculated theoreticaldensity. 30.9% aluminum, by weight of the body, with ance consistingessentially of tantalum.

T able I the bal- UItANSVERSE-RUPTURE STRENGTH DATA FOR INTERMETALLICCUMPUUND-(IUMIOSITIONS Test Modulus of Young's Specimen Nominalcomposition temp. rupture modulus I F.) (p.s.i.) (10 p.s.i.)

AExample 10. 53.6% Be, 46.4% Nb 2,300 39,300

. 2, 500 39,300 40 1 2,750 18,700 20 13-Example 11 v51.6% Be, 48.4% Nb2, 300 55, 800 24 v 2, 500 ,500 18- v v 2, 750 b 32, 000 8 C 50.2% Be,49.8% Nb 2, 300 49, 900 17 1 2,600 50,000 11 2, 750 b 28, 800 4 Seefootnotes at end of table.

The body was then re- Chemical analysis showed '1 1 12 Table IConiinucdI Test Modulus of Young's Specimen Nominal COIHIIOSiLiDfl imnp. rupturemodulus F-EXaiTiDi8 13 45.2% Be, 54.8% Ni) 2, 300 39,0110

G-Exi1mpici4... 56.0% Be, 44.0% Zr 21 300 II 54.1% Be, 45.9% Zr 2, 300

I-Examplc 15 51.5% Be, 48.5% Zr 2, 300

2, 7 .1 49.8% Be, 50.2% Zr 2,3 2,.

K 48.3% Be, 51.7% Zr 2, 300

L 47.1% 130, 52.9% Zr 5, 500

1\IExmnpi0 16 45.7% Be, 54.3% Zr 2,300 I 2, 500

NExampie 17 37.2% Be, 62.8% To 2, 300

35.5% Be, 64.5% To 2, 300

P 32.0% Be, 08.0% To 2,300

Q-Exampie 18 20.8% 130, 70.2% Ta 2,300

R-Exampio 19 53.0% Be, 47.0% Mo 2, 300

SExnmpie 20 46.5% A], 53.5% Ni) 2, 300

2, 31X) 20, 800 T-Exumpic 21- 30.9%Ai,69.1%'1u. 2, 300

I! Approximate composition disregarding minor amounts of impurities. bSpecimens deflected toihc innit niiownhio in the test apparatus, but didnot rupture. Modulus oirupturu reported is based on the loading oitiiespecimen uL Hi0 moment deflection ceased.

Table II OXIDATION TEST DATA F011 INTE RMETALLIC COMPOUN D-GOMIOSITIONS)ecimen Test Weight Miis Specimen Nominal Density Temp. Atmosphere Gain,Penetra- Composition" (percent of C F.) 100 hr. 1.1011

ihoorot.) (mg/cm!) 53.0% Be, 46.4% Ni)... 99. 0 2, 500 Dry air" 10. 71.3 98. 7 2, 500 Moist a 5. i 0. 6 51.0% 130, 48.4% Nb... 100 2, 500 Dryair 3. (i 0. 4 99. 4 2, 700 Moist a 17. 3 2. 0 45.2% B0, 54.8% Ni)...08. 8 2,700 Dry air. 17. 4 2. 0 97. 3 2, 700 Moist air- 17. 3 2. 0 50.0%Be, 44.0% Zr-- 100 2, 800 Dry ML--. 10. 8 1. 4 05. 4 2, 900 Ambient air22. 8 2. 9 09. 0 2, 500 Moist air--- 6. 1 0. 8 54.1% Be, 45.9% Zr-.--100 2, 600 Dry a1r 7.8 1. 0 45.7% Be, 54.3% Zr.... 99. 5 2, 700 .do. 9.4 1. 2 37.2% 130, 62.8% Ta.-. 100 2, 800 0. 9. 2 1. 1 100 2, 500 Moistair. 3. 6 0. 4 35.5% 130, 64.5% T8.-. 100 2, 500 Dry air-- 5. 9 0. 7 96.5 2, 700 ..do... 7. 5 0. 9 29.8% Be, 70.2% T21-.. 07. 7 2, 300 "H. 10-2. 0 0. 2 100 2, 300 Moist air- 6. O (i. 7 100 2, 800 Dry ML. 20. 0 3. 2R-Ex. 19---. 53.0% 130, 47.0% Mo-.- 98. 0 2, 700 -do-- 0. 8 0. 0 98. 72, 500 Moist air 9. 7 0. 8 S-EX. 20 46.5% A1, 535% Nb. 02. 0 2, 500 Dryair- 10. 2 1. 3 9i). 3 2, 500 Moist Bi 7. 8 l. 0 T--Ex. 21 30.0% A1,00.1% Tam. 08.8 2,000 Dry Air. 0.0 0.0 09. 4 2, 500 Moist air. 5. 0 0. 6

I\ Approximate composition disrr-garriing minor amounts oi impurities. hDry uir=1oss than 0.1 mg. of wuwr per iiior (uiiiuoxit gas at roomtemperature). Moist uir=l2 mg. of water por liter (uflineut gas at roomtomporaturv).

Having thus described our invention, we claim: References Cited by theExaminer A composition consisting essentially of from about UNITEDSTATES PATENTS 45.2% to about 53.6%, by weight, of beryllium, and the v574 2 4 5 Canada,

[nuance niobium DAV] D L. RECK, Primary Examiner.

